Plug-in hose connector device

ABSTRACT

A plug-in line connector ( 1 ) for especially simple and secure assembly has a fluid-tight plug-in connection and a locking device ( 25 ), which is very easy to access when its retaining parts are assembled in the axial direction and which is locked so that it cannot be released by passing a locking point. A tension spring, which is formed as a ring and acts as a block, is used for the locking element. This guarantees particularly low activation forces and minimizes axial play.

[0001] The invention concerns a plug-in line connector, more specifically a connector for fluid lines in motor vehicles.

[0002] In particular, air-conditioning systems in motor vehicles, but also other systems, have fluid lines, which connect different components of the system to each other. Such fluid lines must remain leakproof for a long period of time. This condition also applies, in particular, to their connections. On the other hand, the fluid connections between the lines and the connected system components must be able to be established as easily as possible during assembly. Here there are several requirements: for component systems, which are to be mounted in the engine compartment of a motor vehicle, which is the case, e.g., for air-conditioning systems and their components, the accessibility to the individual connection points is usually extremely restricted. There is often no access to the connection points for screwdrivers and other similar tools. Also, other special tools for establishing fluid connections can rarely be inserted into such places. Therefore, the demand has been set to be able to establish connections according to the simplest method possible in terms of processing and without the use of special tools as much as possible. In addition, the connection technology must be independent of the particular training of the assembler in terms of processing. These conditions essentially exclude the possibility of improper assembly.

[0003] In addition to the demand for simple assembly and long-term stable tightness of the connection, the connection should also be as cost-effective as possible under unfavorable environmental conditions, such as temperature fluctuations and effects due to humidity and vibration. The greater the number of connection points in the fluid-guiding system, the more important these conditions.

[0004] A connection system for fluid lines is known from U.S. Pat. No. 5,727,304, which essentially fulfills the afore-mentioned requirements. The system is used for connecting one end of a fluid-guiding tube to a corresponding component system. For this purpose, the relevant tube carries an O-ring in an annular groove on its free end, which contacts the wall of an opening in the component system to be connected in a liquid-tight way. A retaining clamp, which surrounds the tube end and is secured to the component system by means of a bolt, is used mechanically to secure the tube end in the opening. The bolt is realized as a locking bolt and passes through an opening provided for this purpose in the retaining clamp. The locking bolt has a conical head, which connects to a locking shoulder. In the opening of the retaining clamp, there is a snap ring in an annular groove that is open in the inward radial direction and that grips behind the annular shoulder of the bolt as a locking element.

[0005] To connect a tube to a component system by means of this connection technology, the tube end with the O-ring is inserted into the opening and at the same time the retaining clamp with its opening is pushed over the conical head of the retaining bolt until the snap ring grips behind the ring shoulder and the retaining clamp locks to the bolt.

[0006] The problem of the invention, starting from this known line connection device, is to refine this device such that for establishing the connection, the required insertion or activation force can be reduced.

[0007] The problem is solved with the plug-in line connector according to Claim 1.

[0008] The plug-in line connector includes two connector parts, which connect two line channels to each other in the assembled state. In order to maintain this connection for a long period, there is a retaining device, which is formed as a locking device. A tension-spring element formed as a closed ring is used as the locking element. When it is switched into the locking position, at first this is led over a locking projection, wherein it expands in the circumferential direction. The locking projection is preferably rotationally symmetric. Likewise, when it contacts the locking projection, the tension-spring element forms a rotationally symmetric shape. For the transition over the locking projection, it is merely expanded, so that the same radial forces directed inwardly are applied over its entire circumference. Consequently, this uniform force distribution means that the locking element can move relatively easily over the locking projection. The locking forces for establishing the locking connection are correspondingly small. Therefore, the connection can be established by hand without requiring particularly high forces. Thus, the use of such plug-in line connectors can also be used in places that are hard to access and where assemblers can apply only minimal force. In addition, the risk of improper assembly is low. According to experience, connections that are established with minimal force minimize the risk of improper assembly due to the improper use of force.

[0009] The plug-in line connector according to the invention can be used in the air-conditioning system of a motor vehicle, e.g., as a condenser connection, an evaporator connection, a connection to a compressor, or a connection to the thermal expansion valve. Here, a connection between an instrument component and a line is to be established, i.e., one of the connector parts is arranged or formed on the given instrument component. In addition, the plug-in line connector can also be used for connecting two lines. Such plug-in line connectors can also form line bushings, e.g., in the firewall of a motor vehicle. Other fluid lines, such as low-pressure hydraulic lines (feedback lines), fuel lines, oil lines, or water lines can also be connected to the plug-in line connector according to the invention.

[0010] One of the retaining parts of the plug-in line connector according to the invention preferably has an opening in which the tension-spring element is held so that it can move radially but not essentially axially. The opening is a through-hole opening, e.g., through which a corresponding fastening bolt (second connection part) projects. So that the tension-spring element can move radially but not essentially axially, it is received in a corresponding pocket, which can be formed by an annular groove in the walls of the opening of the retaining part. The tension-spring element and the annular groove are adapted to each other in diameter so that the tension-spring element sits with radial play in the annular groove, without being able to fall out of the opening.

[0011] The second retaining part, which is essentially formed by an elongated element with locking contours, is preferably a locking bolt with an annular locking shoulder. The locking bolt can be formed integrally with its corresponding (second) connector part. Preferably, however, it is screwed into this part. For releasing the plug-in line connector, the bolt or the connector part associated with it can be removed, which also allows, e.g., for maintenance purposes, separation of the plug-in line connector.

[0012] Preferably, the tension-spring element is held in the locked state between two, e.g., annular, contact surfaces, of which one belongs to the first retaining part and the other belongs to the second retaining part and which enclose an acute angle opening outwards, particularly at the points at which they contact the tension-spring element. Thus, the surfaces are positioned so that they hold the tension-spring element between each other in the expanded state. The tendency of the tension-spring element to pull together is converted by the angle position of the contact surfaces to each other into an axial tension force, which presses the connecting parts to each other in the locked position. Acute angles between 1° and 15°, preferably of approximately 5° for a slope of the contact surfaces of 20° to 25° against the radial direction, have proven to be especially advantageous for the angle between the two surfaces. The use of this angle produces especially secure locking connections, which can be easily established and which cannot be released through axial forces applied between the connecting parts. Thus, the tension-spring element acts between the contact surfaces oriented like a wedge to each other and the tension of the connector elements acts against each other.

[0013] The tension-spring element is preferably formed as a toroid with circular cross section. It is preferably made from a flexible material, whose flexibility allows a rolling motion about its cord center axis. Thus, the tension-spring element can roll over the associated locking projection, which reduces the insertion forces, i.e., the forces required to establish the plug-in connection, to very low values. The friction that would otherwise occur is thereby reduced. In addition, a clearly defined locking point is generated, which is monitored by the assembler, so that improper assembly, which can result, e.g., through not completely established locking of other locking elements, can be prevented.

[0014] The use of an annular, closed spiral screw has proven to be particularly advantageous as the tension-spring element. The spiral screw is preferably made from spring steel and slides or rolls with low activation forces over corresponding locking projections. The expandability can be set according to requirements through corresponding selection of the spring constants and the wire thickness of the spiral spring element. The annular spiral spring is independent of these values relative to its axial direction, i.e., it is very stiff in the activation direction of the connection elements, which benefits the security of the locking connection. While the individual windings of the closed spiral tension spring are to a certain extent arranged in series relative to their expansion direction (circumferential direction), they are arranged in parallel for the axial direction. In this way, the ratio between stiffness in the axial direction to the stiffness or expandability in the circumferential direction can become very large, which is advantageous for the security of the locking connection.

[0015] The retaining parts can be arranged to the side of the connector parts. Thus, it is possible for one connection part pair (one fluid channel) to have several retaining devices and also for one retaining device to hold several connection devices, which establish the connection between several fluid channels.

[0016] Advantageous characteristics of embodiments of the invention result from the drawing, the description, and the subordinate claims.

[0017] Embodiments of the invention are illustrated in the drawing. Shown are:

[0018]FIG. 1, a motor vehicle air-conditioning system as a schematic block circuit diagram,

[0019]FIG. 2, a plug-in line connector of the air-conditioning system shown schematically in FIG. 1, in longitudinal section,

[0020]FIG. 3, the plug-in line connector from FIG. 2 in perspective sectional representation,

[0021]FIG. 4, a locking device belonging to the plug-in line connector from FIGS. 2 and 3, in sectional representation and at a different scale,

[0022]FIG. 5, the plug-in line connector from FIGS. 2 and 3 in exploded view,

[0023]FIG. 6, an alternative embodiment of a plug-in line connector in perspective view,

[0024]FIG. 7, the plug-in line connector from FIG. 6 in top view,

[0025]FIG. 8, another alternative embodiment of a plug-in line connector in perspective view,

[0026]FIG. 9, another embodiment of the plug-in line connector in top view,

[0027]FIG. 10, a tension spring formed as a closed ring spring in sectional perspective view, and

[0028]FIG. 11, geometric relationships of the retaining device belonging to the plug-in line connector in schematic representation.

[0029] In FIG. 1, an air-conditioning system 2 of a motor vehicle is illustrated as an application example for a plug-in line connector 1 illustrated in FIG. 2. The air-conditioning system includes a compressor 3, a condenser 4, a fluid container with filter dryer 5, and an evaporator 6 as instrument components. These are connected to each other by lines 7, 8, 9, 10, wherein the lines 7, 8, 9, 10 define fluid channels. The evaporator 6 is usually arranged in the interior of a motor vehicle, while the remaining components are arranged in the engine compartment. The interior and the engine compartment are separated from each other by a firewall 11. The lines 7, 10 pass through this wall. Correspondingly, the lines 7, 10 are divided into line sections 7 a, 7 b; 10 a, 10 b. On the firewall 11 there is a bushing element 12, which connects the engine-side part 7 a, 10 a of lines 7, 10 to the passenger-side part 7 b, 10 b of the corresponding line 7, 10. The plug-in line connector 1 illustrated in FIG. 2 can be used for connection of the lines 7, 8, 9, 10 to the instrument components 3, 4, 5, 6, as well as to the connection element 12.

[0030] A first connector part 14 (female connector part) belongs to the line connection device 1, which is provided with a connection opening 15. This forms a fluid channel 15 a, to which a line, e.g., the line 8, which contains a fluid channel 8 a, is to be connected. The line 8 is connected to a second connector part 16 (male connector part), which is to be inserted as a tubular projection into the connection opening 15. The connector part 16 has a first cylindrical section 17, as can be seen especially from FIG. 5, whose outer diameter approximately matches the inner diameter of the connection opening 15 and fits into the connection opening 15 with minimum play. At its free end, the outer diameter of the connector part 16 is reduced, wherein there are one or two locking ribs 18 on its outer circumference. These are used for captive support of an end ring 19, which forms the connection of the connector part 16, e.g., as a plastic ring with a conical inlet diagonal 20. The plastic ring 19 borders in common with the end-side annular surface of the cylindrical section 17 an annular groove 21 (FIGS. 2 and 3), in which an O-ring 23 is arranged or two or more O-rings 23 or other sealing elements are arranged. The O-ring 23 or the other sealing elements is (are) used for sealing the fluid channel 24, which is bordered by the two connector parts 14, 16 from the outside and which is formed by the fluid channels 8 a, 15 a connected to each other.

[0031] In order to keep the connector parts 14, 16 together in the assembled state, i.e., the connector part 16 inserted into the connection opening 15, there is a retaining device 25, which includes a first retaining part 27 and a second retaining part 26. The second retaining part 26 can be formed integrally with the corresponding connector part 16, as can be seen particularly from FIG. 3. The line 8 to be connected is taken away in FIG. 3. It can be connected to the connector part 16 and/or to the retaining part 26 by suitable means, e.g., by means of adhesive connection, solder connection, crimping connection, or some other means. If flexible lines are required, a tubular projection can be provided, as shown in FIG. 2, which extends away from the retaining part 26 and is used as a bearing for a flexible line.

[0032] The retaining part 26 is connected rigidly or releasable to the connector part 16 and has an essentially flat bottom side 28, which in the mounted (assembled) state contacts a corresponding planar surface 29, which is formed on the connector part 14 or if necessary on the retaining part 27. Here, the connector part 14 can be a separate connection element or part of one of the components to be connected. For example, the connector part 14 on the condenser 4, the evaporator 6, the compressor 3, or the connector element 12 and also the fluid container can be provided with a filter dryer 5.

[0033] The connector part 26 has an opening, in the present embodiment a through-hole opening 31 (see particularly FIG. 5), which can be formed essentially as a cylindrical hole. The inner wall of the opening 31 is provided with an annular groove 32, which opens inwardly in the radial direction, as can be seen particularly from FIG. 4. The annular groove 32 has an approximately trapezoidal cross section and supports an annular tension-spring element, in the present embodiment a tension spring 33, whose two ends 33 a, 33 b are connected to each other, so that it forms a closed ring. One of the ends 33 a, 33 b can be inserted into the other. If necessary, they can be connected to each other by a laser spot weld. In addition, they can be connected to each other by an elastomer, which either completely fills the interior or fills at least the region of the ends 33 a, 33 b.

[0034] The tension spring 33, which is illustrated separately in FIG. 10, is wound and dimensioned such that its windings 35 contact each other under a preset tension. It is a pre-tensioned spring element, whose characteristic line can be adapted according to requirements. In the untensioned state, the tension spring has an outer diameter, which is somewhat larger than the inner diameter of the opening 31. Thus, it is held captive in the annular groove 32 and cannot fall out through the opening 31, even if the retaining part 27 does not pass through the opening 31.

[0035] On the other hand, the tension spring 33 has a length such that in the free, untensioned state, preferably slightly more than half of its winding diameter projects into the opening 31. In this way, it can form a locking element for the retaining part 27, which is inserted at another point according to its shape.

[0036] The annular groove 32 forms a pocket for receiving the tension spring 31, wherein the edge 34 facing the planar surface 28 forms a conical [surface], i.e., an annular surface on a conical envelope. With the axial direction A shown in FIG. 4, it encloses an angle of preferably 70°, i.e., it is arranged at an angle of approximately 20° to the radial direction. In contrast, the annular edge 35 of the opposite annular groove 32 can be formed as a planar surface, wherein the slope of this surface is of secondary importance. The groove floor 36, i.e., the outer diameter of the annular groove 32, is arranged or dimensioned such that the tension spring element 33 can be pressed completely into the annular groove 32 as required, i.e., disappears behind the wall of the opening 31, if it is expanded correspondingly.

[0037] The connector part 27 is formed as a locking bolt, which projects from the planar surface 29. The locking bolt 27 can be connected integrally to the connector part 14 if necessary. Preferably, and in the present embodiment, however, it is connected to the connector part 14 so that it can be detached. For this purpose there is a threaded hole 41, which is arranged parallel to the connection opening 15 and at a distance to this opening. Thus, it is positioned so that the bolt 27 does not become stuck in the opening 31 when the connector part 16 is pushed into the connection part 15.

[0038] The connector part 27 has a thread-bearing projection 42, which connects, e.g., to a cylindrical section 43. Its annular end surface 44 connecting to the thread-bearing projection 42 makes close contact with the planar surface 29 when the bolt 27 acting as a connector part is screwed into the threaded hole 41. Thus, the end surface 44 sets the position of a locking shoulder 45 connecting to the cylindrical section 43, which is preferably formed as a conical surface with large opening angle. Radially, it preferably encloses an angle of approximately 25°. Its largest diameter is only slightly smaller than the inner diameter of the hole 31. Its smallest diameter is measured at the transition to the cylindrical section 43, whose outer diameter is smaller than the inner diameter of the free, untensioned tension spring 33. This also applies in the figurative sense if the section 43 is not cylindrical, but instead has another shape, e.g., like a prism. In any case, this section 43 does not contact the tension spring 33 in the locked state.

[0039] An insertion cone 46 contacts the annular shoulder 45, which tapers starting from the largest diameter of the locking shoulder 45 to the free end of the bolt 27. In the present embodiment, the slope of the envelope surface of the insertion cone 46 against the axis A is approximately 8°. Different angles are possible corresponding to the requirements on the activation forces for establishing the locking connection. The length of the insertion cone 46 is dimensioned so that on the free end there is a diameter that is smaller than the inner diameter of the completely free tension spring 33. Thus, the insertion cone 46 is secured in the opening enclosed by the tension spring 33. Instead of the conical shape, other rotationally symmetric shapes can also be used, whose diameter increases to the locking shoulder.

[0040] At its free end, the bolt 27 is provided with an activation device, e.g., an internal hexagonal head 47 or an external hexagonal head or a Torx head, in order to be able to release the bolt 27 from the connector part 14 if necessary.

[0041] The plug-in line connector 1 described thus far operates in the following way:

[0042] First, it is assumed that no assembly has yet been done, i.e., the connector part 16 is not yet inserted into the connector part 14. Thus, the O-ring 23 or the O-rings is (are) untensioned in its (their) appropriate groove 21. The tension spring 33 is also completely untensioned, i.e., it has its smallest inner diameter. However, its outer diameter is at least somewhat larger than the inner diameter of the opening 31, so that it lies securely in its annular groove 32, as shown in FIG. 5.

[0043] If the connector part 16 is now inserted into the connection opening 15 in order to establish the connection, the retaining part 26 with its opening 31 is simultaneously pushed over the conical head of the bolt 27. The annular tension spring 33 thus contacts the insertion cone 46 and is expanded by this cone. Thus, the tension spring 33 slides or rolls about its cord axis S shown in FIG. 10. Even tension springs 33 that are thick and that generate a relatively large force directed radially inwardly, i.e., that expand only with difficulty, roll with minimal resistance on the insertion cone 46. The axial activation forces required for this purpose are small, so that the sliding friction remains low between the edge 35 and the tension spring 33.

[0044] Shortly before the connection part 16 is inserted completely into the connection opening 15, i.e., shortly before the planar surface 28 of the retaining part 26 reaches the planar surface 29 and comes in contact with it, the tension spring 33 has reached the locking shoulder 45. In other words, the locking shoulder 45 is positioned, as can be seen particularly from FIG. 11, such that the distance between the outer end 45 a of the ring shoulder 45 in the radial direction (distance A1) is greater than the diameter D of the tension spring 33 (FIG. 10), while the distance of the smallest diameter (inner end 34 a) of the edge 34 of the opposite locking shoulder (distance A2 in FIG. 12) is smaller than the diameter D of the tension spring 33. As can also be seen in FIG. 11, the inclined position of the participating surfaces 34, 45 provides locking against the radial direction through the tension spring 33 with a circular cross section, without overlapping the surfaces 45, 34 relative to the axial direction A.

[0045] As soon as the tension spring 33 is behind the locking shoulder 45, it snaps into the intermediate space (distance A1) shown in FIG. 11 and pulls together. It wedges itself into the gap between the edge 34 and the locking shoulder 45 and thus pulls the retaining part 26 with great force against the connecting part 14. This creates a locking connection that cannot be released through axial tension. It can be opened again only by removing the bolt 27. Otherwise, a permanent connection is produced. In particular, a large locking force for low activation force (insertion force) is produced. The pulling (tensioning) effect of the tension spring 33, which wedges itself between the inclined surfaces 45, 34, produces an axial, play-free bearing for the retaining device 25.

[0046] The previous embodiment concerns a one-channel fluid connection and a single retaining device for securing it. As can be seen from FIGS. 6 and 7, fluid channels, particularly those carrying high pressure, can also be secured by two retaining devices 25, 25 a. Both retaining devices 25, 25 a are formed to match each other and correspond to the retaining device 25 according to the previous embodiment. As FIG. 7 shows, they can be arranged diametrically opposite each other relative to the line 8. The retaining part 26 is then formed symmetrically in terms of geometry and forces. In addition, it is matched to torsion loads. These are held back by the O-ring 23. In particular, it receives no radial load, which benefits its tightness. This applies to all embodiments with two or more retaining devices 25 (FIGS. 7, 8).

[0047] The arrangement of several similarly formed retaining devices 25, 25 a on a common retaining part 26 is possible since the tension spring element 33 of the corresponding retaining devices 25, 25 a permits a certain amount of radial play. The coaxial position and alignment between the connector parts 14, 16 is determined just from the O-ring 23, but not from the retaining devices 25, 25 a. This also applies to the other embodiments. Thus, the O-ring 23 receives no additional radial load through the retaining device 25 or 25 a and can thus act as an optimum seal. The O-ring determines the radial position and affects the coaxial alignment. It thus creates its own installation position according to requirements. The retaining device adapts to these conditions.

[0048] Another embodiment of the line connector device is shown in FIG. 8. This can be used, e.g., as bushing or connection element 12 from FIG. 1, for connecting lines 7 a, 10 a on both sides of the fire wall 11 to the appropriate line ends. The construction of this plug-in line connector 12 essentially corresponds to that of FIG. 6, wherein the connector part 26 has two line connections 7 a, 10 a. Correspondingly, the connector part 14 is provided with two connection openings that are coaxial to the lines 7, 10.

[0049] While two retaining devices 25, 25 a can be provided for the retaining part 26 with the embodiment from FIG. 7, as can be seen from FIG. 9, the connection can also be secured by means of a single retaining device 25. The connection element 12 a shown here has a connector part 14 with a connection bolt 27 and two connection openings that are arranged diametrically opposite each other and that are not described further. The retaining part 26 has connections for the two lines 7, 10, which are arranged at corresponding positions of the retaining part 26. The retaining device 25 is arranged at the center between the two connections 7, 10, so that it produces symmetrical relationships in terms of forces.

[0050] A plug-in line connector 1 for particularly simple and secure assembly has a fluid-tight plug-in connection and a locking device 25, which is very easy to access when its retaining parts are assembled in the axial direction, and which locks when it passes a locking point so that it cannot be detached. A tension spring, which is formed as a ring and acts as a block, is used as the locking element. This guarantees particularly low activation forces and minimizes axial play. 

1. Plug-in line connector (1) with a first connector part (14) and with a second connector part (16), which define a continuous line channel (24) when the connector parts (14,16) are assembled, and with a retaining device (25), which is used to hold the connector parts (14,15 [sic; 16]) in the assembled state, wherein the retaining device (25) is formed as a locking device and has a tension spring element (33) formed as a closed ring as the locking element.
 2. Plug-in line connector according to claim 1, characterized in that a first retaining part (26), which is connected to one of the connector parts (16), and a second retaining part (27), which is connected to the other connector part (14), belong to the retaining device (25), and the first retaining part (26) has an opening (31), in which the tension spring element (33) is held so that it can move in the radial direction and so that it essentially cannot move in the axial direction, and the second retaining part (27) has a projection (27) that can be inserted into the opening (31) or is formed by this projection and an annular locking shoulder (45) is formed on this projection.
 3. Plug-in line connector according to claim 1, characterized in that the tension spring element (33) is held in the locked state between two contact surfaces (45,34), which enclose an acute angle (α) that opens outwardly between each other.
 4. Plug-in line connector according to claim 1, characterized in that the tension spring element (33) is formed as a toroid with a circular cross section.
 5. Plug-in line connector according to claim 1, characterized in that the tension spring element (33) is flexible so that it can perform a rolling motion about its cord center axis (S).
 6. Plug-in line connector according to claim 1, characterized in that the tension spring element (33) is a spiral spring, whose ends (33 a,33 b) are connected to each other.
 7. Plug-in line connector according to claim 2, characterized in that the second retaining part (27) has a conical insertion section (46), which directly contacts to the locking shoulder (45).
 8. Plug-in line connector according to claim 1, characterized in that the line channel (24) is a fluid channel and for sealing the connector parts (14,16) connected to each other from the outside in the assembled state, there is a sealing device (23) that can move in the axial direction.
 9. Plug-in line connector according to claim 1, characterized in that the connector parts (14,16) are arranged coaxial to each other and the retaining device (25) is arranged at a lateral distance to the connector parts (14,16).
 10. Plug-in line connector according to claim 1, characterized in that the connection device (25) permits lateral movements in the locked state. 